[Effect of vitamin C administration on gastric colonization by Helicobacter pylori]

The conventional treatment of Helicobacter pylori infection consists on antibiotics, to which a small but significant number of patients are non-responders. Alternative treatments to the infection have been suggested, including the use of antioxidants. There has been such increasing interest upon vitamin C since it was demonstrated vitamin C concentrations in the stomach of infected patients are significant lower compared to healthy subjects. Pharmacological doses of vitamin C have been investigated for eradication of H. pylori, with controversial results.

To evaluate the effect of oral administration of vitamin C on H. pylori colonization in the stomach of patients with chronic gastritis and patients with peptic ulcer who had experienced antimicrobial treatment failures.

Protocol I: randomized, double-blinded, placebo controlled study, with patients with chronic gastritis, with no previous treatment for eradication. Protocol II: open, uncontrolled study, with patients with peptic ulcer, with at least two previous treatments for eradication. Treatment consisted of 5 g vitamin C for 28 consecutive days. The effect of the treatment was evaluated by 14C-urea breath test concerning eradication rate, radioactivity variation and infection suppression.

In Protocol I, 38 patients completed the study--21 received vitamin C and 17 received placebo 28 consecutive days. Eradication rates per-protocol analysis with vitamin C were 0, with 95% confidence interval of 0-15%. In Protocol II, eight patients completed treatment. Eradication rate was 0%, with 95% confidence interval of 0-12%. H. pylori load was not decreased.

Administration of vitamin C, in a 5 g/day dosage during 28 days is neither effective for H. pylori eradication nor quantitatively alters the bacteria load in the stomach of infected patients.